Paul D. Spudis is a planetary scientist at the Johns Hopkins
University Applied Physics Laboratory in Baltimore MD.Though he specializes in lunar geology, he
has also studied the geology of Mars, Mercury and many other worlds.He was deputy leader of the Science Team for
the Clementine lunar mission in 1994 and has participated in NASA and National
Academy of Sciences committees that helped shape future space exploration.Dr. Spudis received his B.S. (1976) and
Ph.D. (1982) degrees from Arizona State University in Tempe and his Sc.M.
(1977) from Brown University in Rhode Island.

When and how did you
first become interested in planetary science?How did you focus on the Moon?

Ever since I was a kid in the sixties, I’ve been attracted
to space.I avidly followed the
Mercury, Gemini, and Apollo programs.I
always knew that I wanted to get into space somehow.

I came to planetary science quite late.My initial thought, watching the space
program as an enthusiastic fan, was that it was the engineers who were doing
spaceflight.I figured that if I wanted
to go into space, I would have to learn engineering.So I initially started out in electrical engineering as an
undergraduate.

Then in 1971, I watched the Apollo 15 mission.Dave Scott and Jim Irwin landed near Hadley
Rille, on the Moon.Dave and Jim were
both Air Force pilots, not scientists.However, they were so good and so enthusiastic, and what they did I
thought was so exciting, that I was hooked.

So I read a few books.There were a couple that were quite influential.One was Tim Mutch’s book Geology of the
Moon: A Stratigraphic View.I read it
from cover to cover.I mean, I just
devoured it.I knew after that that
this was my calling.

I changed my major to geology in 1972.I’ve since learned to love geology on the
Earth and I’ve done field work on the Earth, but I approached Earth geology
from the Moon.I graduated from Arizona
State University with a B.S. in geology in 1976.

That last semester at ASU, I saw a flyer on the departmental
bulletin board announcing that NASA was considering having an intern come out
to work at the Jet Propulsion Laboratory on the Viking mission, which was set
to land on Mars that summer.So, I
applied.At the same time, we had a
visit at ASU from Ron Greeley.Because
I was a big Apollo 15 fan, I knew Ron’s name.He had published a paper on the origin of Hadley Rille before the
mission.That was the lava tube/lava
channel hypothesis.

I arranged to meet with him and we ended up spending a
couple of hours, talking about lava tubes and Hadley Rille.That afternoon ended with him offering me a
job at NASA Ames Research Center working on geologic mapping of Mars.After I accepted that, I found out that my
application for the JPL internship had been accepted.So I ended up spending half the summer of 1976 at Ames, then I
went down to JPL in time for the first Mars landing in July.

That was my crash immersion into planetary science.After that summer, I went to Brown
University and started studying planetary science as a graduate student.At Brown, I zeroed in on the moon.

After a year, I got my Master’s.At the same time, Ron Greeley asked me to come work as his
research assistant again.So, I decided
to go earn some money.As it turned
out, when Ron had come to ASU, he was interviewing for a job there.So, I found myself back at ASU in 1978, as
an employee.I figured, as long as I
was there, working in planetary science, I might as well go ahead and get a
Ph.D.I was Ron’s first Ph.D. student.

How did you get your
first job?

Two years into my Ph.D. career at ASU, the U.S. Geological
Survey offered me a job.I had been in
contact with Don Wilhelms, who was the moon guy at the USGS.He became a great inspiration to me.Don came up to me at a scientific meeting
and asked, “How would you like to come to Flagstaff to work?”

Think about it for a minute.Here I am a student with a gross income of $5400 per year, and
I’m being offered a full-time job at the Survey.It took me about a microsecond to agree.Plus, I had always dreamed of living in
Flagstaff.

So, I took that job in May of 1980.I finished my research and wrote my
dissertation as a Survey employee, and then joined the Survey full-time in
1984.I was basically there from 1980
to 1990.

It was difficult to study the moon in the “desert years” of
the 1980s, because it was out of favor in that decade.

About 1990, the
desert years came to an end for a while.You became involved in some high-level efforts to plan our future in
space.How did that happen?

In the mid-1980s, there were a series of conferences and
workshops dealing with a lunar base, which was largely started by Mike Duke and
Wendell Mendell at NASA’s Johnson Space Center.I went to wave the moon flag.We thought seriously about the steps we needed to go back to the moon,
and about what we might do when we got there.

That effort got energized in July 1989, when President Bush
– the first Bush - stood on the steps of the National Air and Space Museum on
the 20th anniversary of Apollo 11 and said that we were going back
to the moon and on to Mars.That was
called the Space Exploration Initiative.

NASA’s response was the
“90-Day Study.”Objectively
speaking, that was not a fumble, but it was perceived as a fumble.The White House was concerned.Here was a Presidential initiative that had
been announced, and their agency had dropped the ball.How were they going to recover from it?

At that time, space policy was in the Vice President’s
office.They came up with the idea of
getting some high-visibility space celebrity to chair a Presidential commission.They asked former astronaut Tom Stafford,
and he agreed.This was called the SEI
Synthesis Group.

This is another of those fortuitous coincidences.I was looking to leave Flagstaff.I had talked to Dave Black, the director of
the Lunar and Planetary Institute in Houston.A few days later he called.He
was involved in the Synthesis Group.He
asked me if I wanted to be involved.

The idea was, we were going to get the best ideas for
exploring space from the aerospace and academic communities, and the
public.We were called the “Synthesis
Group” because we were going to synthesize those ideas and come up with a
“magic architecture” for exploring space.There was a group of about 30 people – mostly engineers.I was one of the few scientists.We received briefings from all the Federal
agencies and all the space groups.

Stafford didn’t get the Space Exploration Initiative
started, but it wasn’t his fault.I
learned a lot.I not only learned a lot
about the engineering you need to go back to the moon –more than that, there
were a lot of policy lessons.

What kind of policy
lessons?

For one thing, I finally learned the true significance of
Apollo.I was totally misled about
it.I had thought that it was about
exploring space, that Apollo was a great visionary leap.

A lot of people in the space business felt betrayed after
Apollo.They had prepared for a world
that didn’t exist.To show you my
naiveté, when I was 13, I went to see the movie 2001: A Space Odyssey, and I thought that was our future.When the year 2001 came and we weren’t on
the moon, a lot of people said, “What happened?”

What happened was, Apollo was not about space.Apollo was not about the moon.My little “eureka moment” came when I watched
a retrospective on Apollo on TV.They
interviewed Frank Borman.They asked
him,“Did you feel like an explorer when you went to the moon on
Apollo 8?”He said, “No, I felt like a warrior.”

At that moment the true meaning of Apollo sank in for me.Apollo was a battle in a war.It was a stick to beat the Russians
with.It was a national security issue.People ask, “Why did we stop going back to
the moon?”Well, it’s obvious. When you
win a battle, you don’t keep fighting it.

There is value to exploration.The problem is, you need a political context to make it
understandable.When we went to the
moon on Apollo, it was perfectly clear to everyone in Washington why they
should vote for it.We couldn’t let the
Russians beat us to the moon.

Nowadays, you get blank stares if you say, “You’re going to
let somebody beat us to Mars?”That
shows that there is no political rationale for it.Fundamentally, that’s why SEI failed.

I was very depressed after the Synthesis Group failed.I thought, “We’ve done all this work, and it
has all been for nothing.”But on
reflection, I think that too was a harsh judgment.We formed networks.The
people who worked together kept in contact.I would argue that Synthesis led directly to Clementine.

I had a feeling there
might be a connection.You were the
Deputy Leader of the Science Team for the Clementine mission, which orbited the
moon in 1994.That was the first
American lunar mission since 1972.

I was in the Synthesis Group with Stu Nozette, of the Lawrence
Livermore National Laboratory.They
were looking at possibly flying a Brilliant Pebble around the moon.A Brilliant Pebble, or BP, is a little
spacecraft.It has eyes, sensors.It has a brain, a computer.And it has mobility, a rocket engine to let
it go on an intercept path.It can
zero in on a warhead, collide with it and render it useless.Brilliant Pebbles was one of the Strategic
Defense Initiatives [SDI] architectures.

The question was, “If you sent one of these BPs to the moon,
could you learn anything about it?”And
the answer was, “Yes.”

The Clementine science team adapted the basic BP sensors to
scientific use.We mapped the moon in
multiple colors in visible light and near-infrared.We turned the lidar, which was a method of determining range to
target, into an altimeter for measuring lunar highs and lows.

The legacy of Clementine, that changes everything, is the
water.We did not have instruments on
Clementine to look for lunar water.But
we improvised an experiment, the Clementine Bistatic Experiment.

We used the spacecraft’s transmitter as sort of a radio
flashlight.We shined this flashlight
into the dark polar regions to see if we could see a glint from any ice.We then looked for the radio reflections
using the 70-meter Deep Space Network antenna on Earth.In the dark regions of the moon’s south
pole, we found an enhancement of the same-sense polarization.That’s a fancy way of saying it’s like a
bicycle reflector glint.We interpreted
it as a sign of water ice.

That interpretation was called into question by some of the
Arecibo radio telescope folks.This
controversy went on for two or three years.We agreed, the debate would be resolved by the Lunar Prospector
spacecraft, launched in 1998.Lunar
Prospector looked for concentrations of hydrogen on the surface.The question was resolved and, yes, by
golly, there is water ice in the dark areas at the lunar poles.

You said that this
changes everything.Why?

Because we now have a reason to go back to the moon. We now have a usable, concentrated resource
in space.We can go to the moon and
manufacture propellant for rockets.

Think about it.What
does it cost to lift something off the surface of the Earth?If you use the Shuttle, it costs tens of
thousands of dollars per pound to get something to low-Earth orbit.But the interesting places are anywhere from
low-Earth orbit to beyond the moon.Going to those places requires propellant.If you have to lug propellant up from Earth, it makes your
mission extremely expensive.But if you
can refuel in space, you can go anywhere in cislunar space – by that, I mean
Earth’s neighborhood.

Just like during Apollo, the political rationale might be
national security.Cislunar space
contains national security assets. We
could, for example, use routine access to build bigger intelligence-gathering
satellites.

There is no way we can lug up from Earth’s gravity well
everything we need to go to the planets and live there.We have to learn how to use off-Earth
resources.The moon has given us a
golden opportunity to learn how to do that.

Let’s go back to how
the moon goes in and out of scientific favor.We explored the moon during Apollo, but stopped.In the 1990s, we explored using Clementine
and Lunar Prospector.Now we’re not exploring the moon.Why not?

The lunar science issue is secondary here.Scientists will follow where the grant money
is.Science is a social construct, like
all fields of human activity.The
search for life is the high scientific priority right now, and that means we’re
sending spacecraft to Mars, because Mars is the one planet we can study which
might have life as we know it.The moon
is perceived to be a solved problem, and therefore unworthy of the engagement
of top-flight scientific minds.

That might actually be changing.The moon is suddenly being considered an important object
again.A special group, chartered by
the National Academy of Sciences, looked at the whole space science exploration
program.When their report came out, lo
and behold, a lunar sample return mission was listed as a high priority
item.A lot of people were surprised.

The reason the moon is now back in favor has to do with the
origin of life.It turns out that there
is a serious problem with the very early lunar cratering history.The question is,“Did all the craters on the moon form in one cataclysmic impact
episode, about 3.9 billion years ago?”If there was a cataclysm, there was no way it could happen on the moon
and not on Earth at the same time.The
interesting thing is, this is around the time when we think life first
emerged.So, people perceive that
there’s a fundamental connection between this issue and life’s origin.

It is also important to understand the early cratering
history of the moon because we use the lunar cratering chronology to calibrate
our geological time scales for all the planets.If we don’t understand lunar history, that means we don’t
understand the history of Mars or the other planets.

In addition to that, Clementine and Lunar Prospector found
the biggest impact basin in the Solar System on the far side of the moon.It is called South Pole-Aitken Basin.When you couple this with the idea that it’s
the oldest impact basin on the moon, and therefore could possibly resolve the
cratering history issue—Viola! It comes up a high-priority scientific
target.

And, I saved the best for last, if you do this mission, you
can rehearse the techniques of Mars sample return.Mars sample return is viewed as the culminating robotic exploration
mission of NASA’s Mars program.

All these threads have converged to make the moon a
high-priority scientific item again, much to the stunned amazement of most of
my scientific colleagues.

What was the most
exciting of surprising moments in your research?

Finding the ice.The
irony here is, I was the guy who, for most of my career, always said lunar ice
as a stupid idea.I had studied lunar
samples.They’re bone dry.I always thought the idea that there might
be ice at the lunar poles was ludicrous, because the moon has no internal
water.I said, “Well, I know it’s been
hit by comets and water-bearing meteorites, but somehow it’s lost that
water.”I just never took it seriously.

Suddenly, I found myself defending this idea that I had attacked.It was a very surprising discovery to
me.It was the thing I least expected
from going back to the moon.

Of course, the final irony is that I think it’s so
important.Not scientifically, though
it does have scientific ramifications – it’s a record of the volatile history
of the inner part of the Solar System for several billion years.But, its real significance is, it’s going to
open up the space frontier.

Have you had any big
disappointments in your research?

I used to tell people that I was sorry I never went to the
moon.One of the reasons I got into
this was because I wanted to do what Dave Scott did on Apollo 15.I wanted to do explore the moon and do
geology.Of course, that’s not going to
happen.

But, you know, that’s silly.I had my moon mission.When I was working on Clementine, I felt like I was on the moon.I remember the first data dump.We had just taken the first images.I recognized a crater in the first
pictures.It was Nansen, up near the
north pole.And when I recognized it, I
felt like I was there.

It’s a very familiar landscape to me.In my mind, the moon is as real as the world
I live in.Of course, I’d love to
explore it.But I’m doing that.I do that every time I fire up my computer
and look at some new data set, or look at some area I haven’t studied before.

It would have been great to go to the moon and walked on
it.I envy the Apollo astronauts that
experience.But you know, I don’t have
many regrets.I have been able to make
a living doing what I love.If you’re
able to say that, you’d better not say that you have many regrets!That’s very ungrateful.And I’m very grateful.

What advice would you
give to students who want to study the moon?

Don’t let anyone dissuade you.Everyone told me I was nuts.In a way they were right.But to
do what you love, you have to be willing to ignore people who tell you that.

Now, when students tell me they want to do what I do, I say,
“Well, you’re not going to find a job—there’s no future—there’s no
growth.”If they say, “Okay” and wander
off, they flunk the first test.They’ve
got to look me in the eye and say, “I’m going to do it anyway.”A couple of students have done that, and
they’re now in the lunar science business.

Find something you love and do it.If you really love it, chances are you’ll be good at it, and
you’ll be able to figure out a way to make a living doing it.

Postscript:This
interview was conducted in late 2002.A
little over a year later, President Bush announced our nation’s return to the
Moon with his Vision for Space Exploration.I had the honor to serve on a commission he assembled to advise on the
implementation of the Vision.We have
determined that not only is lunar polar ice an enabling asset, but the
near-constant sunlight of the poles offer both a power source and a benign
thermal environment, making the lunar poles our first destination for a
permanent outpost on the Moon.